Add report registry and valid periods

internal/report/period.go

@@ -0,0 +1,144 @@
+package report
+
+import (
+	"fmt"
+	"time"
+
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/timeutil"
+)
+
+func Resolve(id ID, req ResolveRequest) (Resolved, error) {
+	return DefaultRegistry().Resolve(id, req)
+}
+
+func (r Registry) Resolve(id ID, req ResolveRequest) (Resolved, error) {
+	definition, err := r.Lookup(id)
+	if err != nil {
+		return Resolved{}, err
+	}
+	return r.resolveDefinition(definition, req)
+}
+
+func (r Registry) BatchReports(batch Batch, req ResolveRequest) ([]Resolved, error) {
+	if req.Location == nil {
+		req.Location = time.UTC
+	}
+	if req.Now.IsZero() {
+		req.Now = time.Now()
+	}
+	switch batch {
+	case Morning:
+		ids := []ID{DailyToday, ThreeDay}
+		if req.Now.In(req.Location).Weekday() != time.Sunday {
+			ids = append(ids, Weekend)
+		}
+		return r.resolveIDs(ids, req)
+	case Evening:
+		return r.resolveIDs([]ID{DailyTomorrow}, req)
+	default:
+		return nil, fmt.Errorf("unknown batch %q", batch)
+	}
+}
+
+func (r Registry) resolveIDs(ids []ID, req ResolveRequest) ([]Resolved, error) {
+	resolved := make([]Resolved, 0, len(ids))
+	for _, id := range ids {
+		item, err := r.Resolve(id, req)
+		if err != nil {
+			return nil, err
+		}
+		resolved = append(resolved, item)
+	}
+	return resolved, nil
+}
+
+func (r Registry) resolveDefinition(definition Definition, req ResolveRequest) (Resolved, error) {
+	if req.Location == nil {
+		req.Location = time.UTC
+	}
+	if req.Now.IsZero() {
+		req.Now = time.Now()
+	}
+	period, err := definition.ResolvePeriod(req)
+	if err != nil {
+		return Resolved{}, err
+	}
+	return Resolved{
+		Definition:  definition,
+		GeneratedAt: req.Now,
+		Timezone:    req.Location.String(),
+		ValidPeriod: period,
+	}, nil
+}
+
+func resolveDailyToday(req ResolveRequest) (timeutil.Period, error) {
+	if !req.Date.IsZero() {
+		return timeutil.CivilDay(req.Date, req.Location), nil
+	}
+	return timeutil.CivilDay(req.Now, req.Location), nil
+}
+
+func ParseStormPeriod(start string, end string, location *time.Location) (timeutil.Period, error) {
+	if location == nil {
+		location = time.UTC
+	}
+	startTime, err := timeutil.ParseStormTime(start, location)
+	if err != nil {
+		return timeutil.Period{}, err
+	}
+	endTime, err := timeutil.ParseStormTime(end, location)
+	if err != nil {
+		return timeutil.Period{}, err
+	}
+	period := timeutil.Period{Start: startTime, End: endTime}
+	if !period.IsValid() {
+		return timeutil.Period{}, fmt.Errorf("storm report requires end time after start time")
+	}
+	return period, nil
+}
+
+func resolveDailyTomorrow(req ResolveRequest) (timeutil.Period, error) {
+	return timeutil.CivilDay(req.Now.In(req.Location).AddDate(0, 0, 1), req.Location), nil
+}
+
+func resolveThreeDay(req ResolveRequest) (timeutil.Period, error) {
+	localNow := req.Now.In(req.Location)
+	endDate := localNow.AddDate(0, 0, 3)
+	end := time.Date(endDate.Year(), endDate.Month(), endDate.Day(), 0, 0, 0, 0, req.Location)
+	return timeutil.Period{Start: localNow, End: end}, nil
+}
+
+func resolveWeekend(req ResolveRequest) (timeutil.Period, error) {
+	localNow := req.Now.In(req.Location)
+	weekday := localNow.Weekday()
+	if weekday == time.Sunday {
+		return timeutil.Period{}, fmt.Errorf("weekend outlook is not scheduled on Sunday morning")
+	}
+
+	daysUntilSaturday := (int(time.Saturday) - int(weekday) + 7) % 7
+	saturday := localNow.AddDate(0, 0, daysUntilSaturday)
+	start := time.Date(saturday.Year(), saturday.Month(), saturday.Day(), 0, 0, 0, 0, req.Location)
+	if weekday == time.Friday || weekday == time.Saturday {
+		friday := start.AddDate(0, 0, -1)
+		fridayEvening := time.Date(friday.Year(), friday.Month(), friday.Day(), 18, 0, 0, 0, req.Location)
+		start = fridayEvening
+		if localNow.After(start) {
+			start = localNow
+		}
+	}
+	end := time.Date(saturday.Year(), saturday.Month(), saturday.Day(), 0, 0, 0, 0, req.Location).AddDate(0, 0, 2)
+	return timeutil.Period{Start: start, End: end}, nil
+}
+
+func resolveStorm(req ResolveRequest) (timeutil.Period, error) {
+	if req.StormStart.IsZero() {
+		return timeutil.Period{}, fmt.Errorf("storm report requires a start time")
+	}
+	if req.StormEnd.IsZero() {
+		return timeutil.Period{}, fmt.Errorf("storm report requires an end time")
+	}
+	if !req.StormEnd.After(req.StormStart) {
+		return timeutil.Period{}, fmt.Errorf("storm report requires end time after start time")
+	}
+	return timeutil.Period{Start: req.StormStart, End: req.StormEnd}, nil
+}